Electric discharge apparatus



' Feb. 26, 1924.;

I 1,485,352 w. D. COOLIDGE ELECTRIC DISCHARGE APPARATUS Fi'led May 20. 1921 Inventor: I William D. Qoolidge,

b hw 4 M His Attorney.

Patented Feb. 26, 1924.

UNITED STATES 1. 5.352 PATENT OFFICE.

WILLIAM D. COOLIDGE, OF SCHENECTADY, NEW YORK, ASSIGN'OR T0 GENERAL ELEC- TB/IC COMPANY, A. CORPORATION OF NEW YORK.

ELEGIBIC DISCHARGE APPARATUS.

Application filed May 20, 1921.

To all whom it may concern:

Be it known that I, WILLIAM D. COOLIDGE, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Electric Discharge Apparatus, of which the following is a specification.

The present invention comprises an improvement in apparatus operable at high voltages in an enclosed tank, as, for example, X-ray apparatus, and it is the object of my invention to provide an appara us which may be used with greater safety by the operator than apparatus of the construction heretofore used.

In order to reduce the danger of electric shock high voltage devices, particularly X- ray tubes, have been enclosed in an oil-filled container together with the transformer supplying energy. Such a device is shown in \Vaite Patent 1,334,936 of March 23, 1920. In the device described in this patent the X-ray tube is connected directly to the high potential transformer secondary, so that all of the high voltage parts are buried in oil and are inaccessible. The low potential conductors are led through insulating bushings through the container which consists of metal. In cases requiring such a device to be adjustable to various positions special relatively movable contacts are required in the form of brushes or the like.

In accordance with my invention I have provided a totally enclosed X-ray apparatus having but a single leading-in conductor,

thereby reducing complications. In my improved. apparatus, which is not limited necessarily in its usefulness to X-ray production, I have provided aseparate external insulating transformer having a grounded secondary terminal, the primary terminal of -the transformer in the tank, also being grounded.

My invention is illustrated diagrannnati cally in the accompanying drawing as applied to an X-ray tube.

Referring to the drawing, the X-ray tube 1 is of the usual construction described in prior patents and other publications. The cathode 2 and the anode 3 are connected respectively by conductors 4, 5, to the secondary termlnals of a high potential transformer 6. The cathode is heated by a heating circuit completed by a conductor 7,,

Serial No. 471,289.

energy being supplied conveniently by end turns of the secondary winding as indicated. The X-ray tube and high tension transformer are located within a tank, preferably consisting of metal. The tube tank is indicated by dotted lines. One primary terminal 8 of the transformer 6 is connected to the tank and grounded as indicated. The

opposite conductor 8' is insulated from the tank as indicated at 9. It is connected to the secondary winding of a transformer 10, the opposite terminal of which is grounded at 11. The transformer 10 may'have a one to one ratio, its function being mainly to provide suitable insulation between the electric service lines 12, 13, and the transformer 6,

but I have indicated one of the terminals as adjustable so that the supply voltage may be varied as desired. The transformer'lO need not form a physical part of the a paratus. -It may be located in any suitab e position removed from the high tension outfit. Frequently one of the conductors leading to the main service transformer 14 is grounded as indicated so that the opposite conductor as 12 could be connected directly to the ungrounded conductor 8' which contains rubbing or sliding contact devices diagrammatically indicated at 15. I However, this would require the operator to test out his connections before installing the apcluding one Point of the primary of said transformerand said container, a leadingin conductor insulated from said container connected to another point of said primary and a local insulating transformer external to said tank having one'terminal of the secondary grounded and another terminal connected to said leading-in conductor.

X-ray apparatus comprising the combination of an enclosed tank, a transformer-therein having a grounded primary terminal, an X-ray tube in said tank connected to the seconda terminals of said transformer, an externa transformer having a grounded secondary terminal, an electrical conductor connecting the ungrounded. primary terminal of the enclosed transformer with the ungrounded secondary of the ex having a grounded terminal and a supply conductor connecting an ungrounded terminal of said external transformer and an un rounded terminal of the transformer inc osed in said tank.

4. An electrical discharge apparatus comprising a metal tank, a transformer therein aving a primary winding connected to said tank at one terminal, a conductor connected to the. opposite terminal led through the wall of said tank and insulated therefrom, w an electrical discharge tube in said tank operatively connected to said transformer, an external transformer connected at one terminal to said insulated conductor and a ground connection for the opposite terminal of said transformer.

Inwitness whereof, I have hereunto set my hand this 19th-day of May, 1921.

WILLIAM D. COOLIDGE. 

